The Manchester United star missed the end of the season with a groin injury and will start training a week before the rest of Roy Hodgson's squad

The Manchester United striker is a major injury worry after missing the end of the season with a groin problem. That has raised fears about a player whose fitness issues have dogged him in previous tournaments.

He caused a storm by going to party in Las Vegas just a month before Euro 2012 but has decided for a totally different approach this time.

And England boss Roy Hodgson revealed Rooney is flying to Portugal this week - a week earlier than the rest of the squad - to try to prove he will be ready for Brazil next month.

Hodgson said: “He’s going to with two fitness trainers. Tony Strudwick has been in touch with us, who wanted to know about the pitch in Vale de Lobo. This is a free week, a week where players go off. Many do go to Portugal, where they have homes.

“Wayne is so determined to be up and running when we get there on the 19th. He’s got a house out there in Portugal. He’s not alone. A few of them are going out to Portugal.

“If they’ve got houses out there, that’s where they go on their week off. They don’t all go to Dubai and Las Vegas.

“His attitude is that he’s desperate to be up and running on the 19th. I’m not as desperate for him to be fully fit on the May 19th. I’m thinking more of the 14th of June, but it’s still quite laudable that that’s the way he thinks and I’m not trying to dissuade him.

“But if I do get there on the 19th and the fitness people say he needs two or three days, I won’t be shedding any tears.”

England jet out to Portugal next week to begin their World Cup preparations before two friendlies in Miami.

Rooney is an injury concern but the biggest other worries are United defender Phil Jones and Arsenal midfielder Alex Oxlade-Chamberlain.

Everton youngster John Stones is on standby for Jones while Arsenal boss Arsene Wenger believes Oxlade-Chamberlain will have to prove his fitness before the squad leaves their Portugal training base.